Have a new (3 weeks old) 2008 MMH; today was the first chilly morning (35 outside). First time I've used the heater. The heater was very slow to warm up, only worked when the ICE was on, otherwise blew cold air in EV. Even with the automatic climate control set at 90 the air from the vents was lukewarm at best. I had an engine block heater installed a week ago but didn't use it last night (could the dealer have screwed something up?-- they told me this was the first block heater they've installed) The engine itself must have been warm because it went into EV mode as expected, which, as I understand it, requires a coolant temp of 160. Is the water pump mechanical? i.e., does it circulate coolant to the heater core only when the engine is running?-- but even with the engine running the heat was poor.

Is this behavior normal? Or off to the dealer?

Thanks

 

Does NOT sound normal.

My 2005 gets warm air fast. Faster than any car I've ever owned.

There is a belt driven mechanical pump for the engine cooling, and there is an electrical pump for cabin heat. This one should work full time, EV or not. There is a second loop, and a second pump for electronics cooling.

Have it looked at. You should have "warm" air in less than 1 minute, and "hot" air in less than 5 minutes. Maybe sooner than that if you use the block heater. -John

Go Socks!

 

Your MMH isn't operating correctly. The heater system is provided with hot water from both the engine mechanical pump and an electric pump, so in EV you should get plenty of heat. My 2007 FEH provides heat quickly and amply even in zero degree weather in all modes.

 

very helpful, thanks. Off to the dealer tomorrow. Wonder if they disconnected the electric pump when installing the block heater?

 

Dont know about the 08 but the 07 doesnt go near anything in the heater system. I installed mine last thursday.

 

As the others have said, heat starts pretty quick. I was suprised that I start to notice heat within about 1/2 - 1 mile when I start off in the morning. Small block engines to seem to provide heat quicker then larger engines.

A 04 PT Crusier we had provided heat pretty quickly while the 94 XJS with it's 6L motor was pretty slow to provide heat (but not slow on the highway! )

 

Because of the way the EPA does the certification of emissions they need the cars to come up to temp really fast as cold start is part of the test. This is also why we cant start in ev when cold. Anytime the manufactures can design a new engine they will design a smaller volume engine cooling system so it will warm up VERY quickly. I have been noticing this since about 98 but rapily starting about 03.

 

FYI, it was 38 degrees today, when I started my brand new MMH 2008. It took lest then 1.5 miles to warm the temp. in the cabin to 72.

 

Evidently was a bad pump on the heater core coolant circuit. Based upon info here, was able to help dealer with dx. Work fine now. Thanks, all.